The sum of the numbers of the central diamond of the multiplication table [1..k] X [1..k] for k=2*n-1.

A357042

The sum of the numbers of the central diamond of the multiplication table [1..k] X [1..k] for k=2*n-1.

Terms

    a(0) =1a(1) =20a(2) =117a(3) =400a(4) =1025a(5) =2196a(6) =4165a(7) =7232a(8) =11745a(9) =18100a(10) =26741a(11) =38160a(12) =52897a(13) =71540a(14) =94725a(15) =123136a(16) =157505a(17) =198612a(18) =247285a(19) =304400a(20) =370881a(21) =447700a(22) =535877a(23) =636480a(24) =750625a(25) =879476a(26) =1024245a(27) =1186192a(28) =1366625a(29) =1566900

External references